Patent EA-003893-B1 (EA)
Title: Method of treating a hydrocarbon-bearing formation
Inventor: REES DAVID CHRISTOPHER
IPC: C09K8/58
Filed: 2000-11-03
Abstract: 1. A method of treating a hydrocarbon-bearing measure, which comprises: bringing micro-organisms into contact with the measure; supplying the micro-organisms with growth factors; allowing the micro-organisms to multiply using the hydrocarbon as their main carbon source, thereby establishing a biomass layer which carries out substance functions, dissociating the hydrocarbon; and in which the growth factors are supplied by means of a controlled-release medium and are distributed through the measure by carrying out their supply over a predetermined period of time. 2. A method as claimed in Claim 1, in which the micro-organisms are in the form of anaerobic or facultative anaerobic bacteria. 3. A method as claimed in Claim 1 or Claim 2, in which the controlled release medium comprises a porous inert carrier impregnated with the growth factor. 4. A method as claimed in Claim 1 or Claim 2, in which the controlled release medium comprises micro-capsules containing the growth factor. 5. A method as claimed in Claim 1 or Claim 2 in which the controlled release medium comprises a micro-emulsion or micro-pellets incorporating the growth factor. 6. A method as claimed in any preceding Claim, in which the growth factor is injected into the measure using water. 7. A method as claimed in Claim 6, in which the injection water also contains a source phosphates and an electron acceptor. 8. A method as claimed in Claim 7, in which the bacteria are either already present in the measure or are introduced simultaneously with the growth factor, phosphates and electron acceptor. 9. A method as claimed in Claim 7 or Claim 8, in which the electron acceptor is nitrate. 10. A method as claimed in any preceding Claim, in which substantially no oxygen is supplied with the injection water. 11. A method as claimed in any of Claims 2 to 10, in which the bacteria substantially comprise species of sulphate-reducing bacteria, nitrate-reducing bacteria, iron-reducing bacteria or acetogenic bacteria. 12. A method as claimed in any preceding Claim, in which the growth factor is introduced into the measure continuously. 13. A method as claimed in any preceding Claim, in which the superficial velocity of the injection water through the measure is between 0.1 and 5m/day. 14. A method as claimed in any preceding Claim, in which the growth factor is vitamins. 15. A method as claimed in Claim 14, in which the vitamins comprise one or more of: B 12, biotin, folic acid, nicotinic acid, aminobenzoic acid, calcium pantothenate, pyridoxine HCl, riboflavin, thiamine and thioctic acid. 16. A method as claimed in any preceding Claim, in which the concentration of the vitamins when released into the injection water is in the range of 0.1 to 100. 17. A method as claimed in any preceding Claim, in which the microorganisms produce surfactants, which act to dislodge the oil. 18. A method as claimed in any preceding Claim, in which the measure is a hydrocarbon-contaminated soil. 19. A method as claimed in any of Claims 1 to 17, in which the measure is a hydrocarbon-containing rock formation. 20. A method as claimed in Claim 19, in which the formation includes an inlet and an outlet. 21. A method as claimed in Claim 20, in which the inlet is at a first location and the outlet is at a second location spaced apart from the first location. 22. A method as claimed in Claim 20, in which the inlet and outlet are one and the same. 23. A method as claimed in any of Claims 19 to 22, applied to more than one outlet from the oil-bearing formation.